Tandem draft rigging



June 17, 1930.

J. F. O" CONNOR TANDEM DRAFT RIGGING Filed Feb. 27, 1928 Patented June 17, 1930 UNITED STATES Parent oFFicE JOHN F. OCONNOR, OF CHICAGO, ILLINOIS, ASSIGNOR TO W. H. MINER, INQ, OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE TANDEM DRAFT RIGGING Application. filed February 27, 1928.

This invention relates to improvements in tandem draft riggings.

There are, at the present time, many thou sands of freight cars in service'which are equipped with tandem stop castings or cheek plates, originally intended for use with tandem arranged springs. Due to the heavier demands for shock absorbing capacity arising because of the greater lengths of trains now customary, it has been found that the ordinary tandem spring gear is not of suificient capacity to properly. withstand the shocks encountered, particularly under buff. The great number of such tandem stop castings repre sents a large investment for the railroads, which the railroads cannot afiord to lose by removing the tandem castings and replacing the tandem spring gears by friction gears with different stop castings. I am aware that efforts have heretofore been made to utilize friction shock absorbing units with tandem castings, but the same have either involved too much initial expense or have not provided for a sufiiciently easy draft action.

One obj eot of my invention is to provide a draft rigging, wherein may be utilized tandem stop castings now in service in combination with a shock absorbing unit so arranged as to provide combined friction and spring capacity in buff, with an easy spring action only in draft.

Another object of my invention is to pro- Vide an arrangement of the type just indicated, wherein the buffing loads are distributed to four sets of shoulders of the stop castings to thereby obtain a better distribution of the shocks to the draft sills.

A more specific object of my invention is to provide a novel friction unit which may be used in combination with those types of tandem stop castings that employ follower supporting straps, so that separate means are rendered unnecessary for supporting the improved friction unit.

In the drawing forming a part of this specification, Figure 1 is a horizontal, longitudinal, sectional view of a portion of a railway car showing my improvements in connection therewith. Figure 2 is a front end elevation of the improved friction unit, and Figure 3 Serial No. 257,126.

is a vertical transverse sectional view, c0rresponding to the section line 33 of Figure 1.

In said drawing, '1O l0 denote channel draft sills of a car underframe, to the inner faces of which are secured tandem stop castings, each designated generally by the reference character A. Associated with the stop castings is my improved friction unit B; a spring resistance C; a combined spring follower and cap D; a front main follower E; a rear main follower F; a yoke G; and a coupler H.

Each of the tandem stop castings A is of that well known type having a front main stop shoulder 11; a front intermediate shoulder 12; arear intermediate shoulder 13; a rear main stop shoulder 14; and corresponding limiting stop shoulders 111, 112, 113, and 114C. The coupler H, which is illustrated, is of that type to whicha yoke strap G may be riveted, as indicated at 1515, although other forms of yokes may be used since this forms no part of my improvements. The followers E and F are of the usual rectangular plate type. V

The improved friction'unit B preferably comprises a rectangular friction shell 16, having a top flat wall 17, a bottom flat wall 18, vertical fiat sine walls 1919; and laterally extended, vertically arranged heavy lugs or preferably be aligned with the front limits ing stop shoulders 111. The width of the shell is such that the samewill be readily received between the front set of limiting stops.

On the interior, the shell 16 is shown provided with removable liners 2121, having inner friction surfaces preferably converging inwardly of the shell. Cooperable with the shell friction surfaces are wedge friction shoes 22-1-22 and co-operable with the latter is a pressure transmitting wedge 23.

v The follower spring cap D is preferably in the form of a casting of rectangular cross section having an integral rear wall 24, side walls 25, and laterally projecting, vertically extending lugs or shoulders 26, so positioned that the same normally engage the limiting stop shoulders 113, as shown in Figure 1. Said lugs or shoulders 26 are of such Width horizontally that the same permit of a draft movement corresponding to the desired amount.

The spring resistance C preferably comprises an outer heavy coil 27 and a nested lighter inner coil 28, both bearing at their rear ends on the rear section of the member B. The outer coil 27, at its front end, seats against an annular flange 29 formed at the inner end of a cup-shaped spring follower 30, the front end of the inner coil 28 extending within the cup section and bearing against the bottom wall thereof. The overall length of the friction spring device is maintained by a bolt 31 in a well known manner.

By employing a rectangular friction shell, as illustrated, it will be observed that I am enabled to support the same in proper horizontal position by means of the follower guide straps 3232, which extend longitudinally of the stop castings and are detachably supported by removable short bolts located at the front, intermediate, and rear main stops of the castings, as indicated at 33, 34;, and 35, respectively, the details of which I do not deem it necessary to illustrate, since their construction is well known.

By referring to Figures 2 and 3, it will be noted that the straps extend partially under the fiat bottom wall 18 of the shell and also under the lugs or shoulders of the friction shell. With this arrangement, I eliminate the necessity for saddle plates or the like.

In operation, upon a buff stroke the friction shell remains stationary and the movable wedge friction elements are forced inwardly thereof, a yielding resistance with a gradually increasing amount of friction being afforded by the spring unit C. The buff stroke is limited by the front follower E coming into contact with the limiting stop shoulders 111, and it will be noted that the rear follower F is in engagement with the rear main stop shoulders 1 1, and the shoulders 26 of the follower "ap D are likewise in engagement with the Inn. iting stop shoulders 113, so that the ultimate load is transferred to the stop castings at four sets of shoulders, thus obtaining a uniform distribution of the load, as will be obvious. In a draft movement of the coupler, there is no friction action, but merely a spring resistance obtained by the forward movement of the rear follower F and follower cap D, which are limited in their draft movement by the former engaging the limiting stop shoulders 114-. and the latter engaging the rear intermediate shoulders 13.

As will be apparent from the preceding description, considered in connection with the drawing, the friction unit proper may be manufactured at comparatively small expense, since the shell is of relatively small size. The follower cap D is a simple casting and likewise can be manufactured at small expense and it will further be noted that I am enabled to employ a relatively long spring unit so that there is no danger of the same becoming set or overloaded, which might otherwise occur if a short spring were utilized. Further, the arrangement permits of the reemployment of the follower guide straps now found on thousands of cars, so that the railroads are not required to supply saddle plates or go to the expense of drilling the flanges of the draft sills for the r ception of bolts or other means necessary to secure saddle plates in position.

lVhile I have herein shown and described what I consider the preferred manner of carrying out my invention, the same is merely illustrative, and I contemplate all changes and modifications which come within the scope of the claims appended hereto.

I claim:

1. In a draft rigging, the combination with tandem stop castings having front main and intermediate stops, rear intermediate and main stops, and corresponding limiting stops; of a friction shell anchored to said castings between the front intermediate and corresponding limiting stops; wedge friction elements co-operable with said shell; a spring extending from said shell approximately to the rear main stops; and means associated with the inner end of said spring, said means having a plurality of follower acting portions movable between and respectively co-operable with the rear main stops and corresponding limiting stops, and the rear intermediate stops and corresponding limiting stops, whereby a spring friction action is obtained in buff and a spring action only in draft.

2. In a draft rigging, the combination with tandem stop castings having front main and intermediate stops, rear intermediate and main stops, and corresponding limiting stops; of a friction shell anchored to said castings between the front intermediate and corresponding limiting stops; wedge friction elements co-operable with said shell; a spring extending from said shell approximately to the rear main stops; a follower cap at the rear end of said spring and having laterally projecting shoulders co-operable with the rear intermediate and corresponding limiting stops; and a rear follower against which said follower cap bears.

In witness that I claim the foregoing I have hereunto subscribed my name this 21th day of February, 1928.

JOHN F. OCONNOR. 

